In communication systems, signals are often transmitted from a source communication device to a target communication device via a wireless or free space medium. These communication devices typically employ a transmitter for transmitting signals long distances via the wireless medium. In many cases, the transmitter is operated continuously, whether or not signals are being transmitted. In some cases, operating a transmitter in a continuous manner may be acceptable. However, when the power source is limited, this may not be desirable since the communication device may not be operated continuously for a desirable long time.
For instance, many communication devices are portable, such as cellular telephones, personal digital assistants (PDAs), handheld devices, and other devices. Portable communication devices typically rely on a limited power source, such as a battery, to perform the various intended operations. A limited power source typically has a continuous use lifetime that depends on the amount of power used by the portable device. It is generally desirable to extend the continuous use lifetime as much as possible. Accordingly, portable communication devices are more frequently designed to consume less and less power.
One technique for operating a transmitter in a more power efficient manner is to use pulse-based modulation techniques (e.g., pulse-position modulation) to transmit signals. In such a system, a transmitter may be operated in a relatively high power consumption mode during the transmission of a pulse signal. However, when the transmitter is not being used to transmit the pulse signal, it is operated in a relatively low power consumption mode in order to conserve power. Data, in the form of pulses, may be transmitted in frames. In such a case, a receiver needs to detect the frames in order to extract the data.